Diabetics with neuropathy are at risk for limb loss due to amputation. Neuropathy and loss of sensation can lead to skin ulcerations that are slow to heal under conditions of low peripheral blood flow. Infection, gangrene and amputation are common occurrences. Early detection of the onset of vascular complications is a critical step in the optimal management of diabetic patients. We plan to develop a system (sensor, monitor and algorithms) that will enable the physician to non-invasively quantify the level of peripheral capillary blood flow in diabetics and anticipate vascular-related complications. The ability to non-invasively monitor peripheral capillary blood flow will: 1) provide an early warning of vascular complications; and 2) help manage therapies that address circulatory problems. The monitoring of peripheral blood flow will help prevent amputations. In the case where an amputation is indicated, quantitative knowledge of peripheral blood flow will help determine the optimal location of the amputation that preserves as much of the limb as possible and insures that the limb flap has adequate blood flow to heal. The goal of this project is the development of a non-invasive clinical device to monitor capillary blood flow. In Phase 1 we will develop a prototype system to quantify peripheral microcirculation using a thermal-based technique (Specific Aims 1 and 2) and we will test this system in the laboratory (Specific Aim 3) and in an animal model (Specific Aim 4). In Phase II, we will develop a beta system and conduct a clinical study to demonstrate the safety and efficacy of the non-invasive perfusion measurement in a diabetic population. The routine clinical use of this device will substantially reduce the need for amputations in diabetics. [unreadable] [unreadable] [unreadable]